143gr Hammer Hunters in 7mm Rem Mag 4831 SC

[Jbumblebee]

7 mm rem mag
Remington 700 ADL 24" barrel
1:9.25 Twist
Gun Werks brass
Federal Large Rifle Magnum primers
100 yards, no wind, cloudy
various c.o.a.l to fit magazine
4831 SC

63gr 3.688 2721
64gr 3.683 2811
65gr 3.683 2685
66gr 3.683 2874

I can't explain the drop in velocity with 65gr. More work is needed and a new battery for the Chronograph

 

[PA Plumber]

See below...

 

[PA Plumber]

7 mm rem mag
Remington 700 ADL 24" barrel
1:9.25 Twist
Gun Werks brass
Federal Large Rifle Magnum primers
100 yards, no wind, cloudy
various c.o.a.l to fit magazine
4831 SC

63gr 3.688 2721
64gr 3.683 2811
65gr 3.683 2685
66gr 3.683 2874

I can't explain the drop in velocity with 65gr. More work is needed and a new battery for the Chronograph

Hmmm. Muzzle Velocities look slow to me.
Not an expert with anything, except maybe plumbing, and that's even iffy.

 

[Jbumblebee]

Hmmm. Muzzle Velocities look slow to me.
Not an expert with anything, except maybe plumbing, and that's even iffy.

They probably are slow. I'm building up nad just returned from adding two each of 67, 68, 69, and 70gr.

I'm an ex spert.... ;-)

 

[PA Plumber]

With the low velocities posted and the listed amount of powder used, I'm getting a little feeling in the back of my mind that something isn't quite right. I'd be hesitant to keep adding powder to that combination. At 65 gr of 4831SC I'd expect to be well into the 3k fps range.
It might not hurt to touch base with Hammer and see what they say.

 

[RockyMtnMT]

Lower engraving pressure will result in lower than expected vel for a given charge. Lower engraving pressure may take a bit more powder to get to vel and generally result in more vel at top end pressure.

Also inconsistent chrono readings may be playing into this.

 

[Jbumblebee]

I'm going to stop by Cabelas this Friday. They may have a MagnetoSpeed V3 or just the MagnetoSpeed in stock. Plus, I'll get a new battery for my Pact1.

 

[Rosebud]

Pick a faster burn powder.4350 etc.

 

[Dr. Vette]

What chronograph? How much sun?

With the 146HH in my 7mm Wby I'm getting 3296fps average with my Labradar using MRP.
You have a lot of speed left on the table if you want it.

 

[Jbumblebee]

What chronograph? How much sun?

With the 146HH in my 7mm Wby I'm getting 3296fps average with my Labradar using MRP.
You have a lot of speed left on the table if you want it.

It was a sunny morning and my Pact1 chronograph is close to 15 years old and the battery wasn't new.

 

[Dr. Vette]

It was a sunny morning and my Pact1 chronograph is close to 15 years old and the battery wasn't new.

Sun can drastically affect the accuracy of that type of chronograph.
I still own my Chrony, but don't use it any more after seeing changes of 100fps depending on the light.

 

[Jbumblebee]

I'm debating on a new Chrony. I found a load for the 143 Hammer Hunter and one for the 160 Shock Hammer that grouped together. I'm pursuing that along with the higher velocity. A new battery for the Pact1 is the easiest and least expensive start.

 

[Dr. Vette]

I'm debating on a new Chrony. I found a load for the 143 Hammer Hunter and one for the 160 Shock Hammer that grouped together. I'm pursuing that along with the higher velocity. A new battery for the Pact1 is the easiest and least expensive start.

Also, shoot on overcast days.

I've had times the Chrony was very similar to my Labradar but it had to be an overcast or cloudy day.
Sunny day? Forget it.

 

[Jbumblebee]

I'll remember that, thanks. We get quite a few cloudy days here in Oregon.